It's now easier to manage multiple calendars in Google Calendar. Calendars that you manage and other calendars that you don't manage (but can view) are more clearly identified. Clicking the name of a calendar lets you show or hide that calendar in the main area of the window. To add a contact's calendar, add a public calendar, or import calendar data, click the 'Add' link near the bottom left of the screen.

Editions impacted:
Standard, Premier, Education, Team and Partner Editions

Languages impacted:
US English

How to access what's new:
Sign in to Google Calendar to access these interface improvements.

For more information:
http://www.google.com/a/help/intl/en/users/calendar.html